1. Field of the Invention
The present invention relates to a liquid processing apparatus and a liquid processing method for applying a predetermined liquid processing or a predetermined drying processing to various substrates such as a semiconductor wafer and an LCD substrate.
2. Description of the Related Art
In the manufacturing process of, for example, a semiconductor device, used is a wafer cleaning apparatus for cleaning a semiconductor wafer used as a substrate with a cleaning liquid such as a predetermined chemical liquid or a pure water so as to remove contaminants such as particles, an organic contaminant, and metal impurities from the wafer or for drying the wafer by removing liquid droplets from the wafer by using an inert gas such as a nitrogen gas (N2) or a volatile and highly hydrophilic IPA vapor.
Known is a cleaning-drying apparatus of this type, in which a plurality of wafers are subjected to the processing in a batch system. For example, a container housing a plurality of wafers such that the main surfaces of these wafers are held substantially parallel is disposed in a predetermined position of a cleaning-drying apparatus. The plural wafers housed in the container are simultaneously taken out by using a transfer mechanism so as to be transplanted onto a rotor for holding the wafers. Then, a predetermined liquid processing is applied to the wafers held by the rotor within a chamber, followed by applying a drying processing to these wafers. Finally, the wafers after the drying processing are transferred again into the container by using the transfer mechanism.
The process between the cleaning step and the drying step is carried out in general such that the chemical liquid used for the processing with the chemical liquid is washed away by using IPA, followed by applying a water cleaning processing using a pure water and subsequently applying a drying processing using an IPA gas or a nitrogen gas.
In recent years, there are increasing demands for omitting the step of washing away the chemical liquid with IPA so as to shorten the process step and, thus, to improve the through-put and for omitting the use of IPA so as to reduce the processing cost. However, the chemical liquid is left attached to, for example, the inner wall of the chamber after the processing with the chemical liquid. Also, the chemical liquid is not completely discharged after the processing with the chemical liquid so as to remain to some extent in the bottom portion of the chamber. If a water wash is applied under such a state after the processing with the chemical liquid, the chemical liquid is diluted with the pure water so as to form, for example, a strongly alkaline aqueous solution. If the strongly alkaline aqueous solution remains within the chamber for a considerably long time, the wafer tends to receive damage.
Also, the chamber forming the process space for applying a liquid processing has a sealing structure so as to prevent the process liquid from being scattered to the outside during the liquid processing. In general, a sealing material such as rubber is used for forming the sealing structure. It is necessary to renew the sealing material abruptly or periodically because the sealing material is deteriorated by, for example, the chemical liquid or is deteriorated with time. However, the conventional liquid processing apparatus is not sufficiently satisfactory in operability and maintenance capability. For example, it is necessary to detach the chamber itself for renewing the sealing material.
Further, it is required to maintain a high quality of the substrate and to improve the reliability of the substrate by decreasing the amount of the particles attached to the main surface of the substrate and by preventing the traces of the droplets of the chemical liquid from remaining on the main surface of the substrate during the processing with a chemical liquid and during the drying processing. However, the requirement has not yet been satisfied sufficiently.
A first object of the present invention is to provide a liquid processing apparatus and a liquid processing method that prevent damage from being done to the substrate by the mixing of process liquids. A second object of the present invention is to provide a liquid processing apparatus that permits performing a liquid processing without using a process liquid used in the past as an intermediate liquid for preventing different process liquids from being mixed with each other. A third object of the present invention is to provide a liquid processing apparatus that facilitates the renewal of the sealing material and the maintenance. Further, a fourth object of the present invention is to provide a liquid processing apparatus capable of maintaining a high cleanliness on the main surface of the substrate and a liquid processing method using the particular liquid processing apparatus.
According to a first aspect of the present invention, there is provided a liquid processing apparatus for performing a liquid processing by supplying a process liquid to a plurality of substrates, comprising a rotor capable of holding said plural substrates a predetermined distance apart from each other, a chamber capable of housing said rotor and arranged slidable between a process position and a retreat position, a process liquid spurting nozzle for spurting said process liquid onto the substrates housed in said chamber, and a cleaning mechanism for cleaning said chamber, wherein said cleaning mechanism includes a process space-forming member positioned inside said chamber in its retreat position and forming a cleaning process space in the clearance between said chamber and said process space-forming member, a cleaning liquid spurting nozzle for spurting the cleaning liquid into said cleaning process space, and a gas spurting nozzle for spurting a drying gas into said cleaning process space.
According to a second aspect of the present invention, there is provided a liquid processing method for performing a liquid processing by supplying a process liquid to the substrates held by a rotor capable of holding a plurality of substrates a predetermined distance apart from each other by using a liquid processing apparatus including a fixed substantially cylindrical outside chamber, a substantially cylindrical inside chamber capable of being housed inside said outside chamber and slidable between a process position and a retreat position, and a cleaning mechanism for cleaning said inside chamber in its retreat position, said method comprising a first step for applying a liquid processing to said substrates by using said inside chamber in its process position, and a second step of applying a liquid processing to said substrates by using said outside chamber with said inside chamber by moving said inside chamber to its retreat position, and a third step of cleaning said inside chamber by said cleaning mechanism at a predetermined timing in its retreat position.
As described above, a cleaning mechanism of the chamber is utilized in the liquid processing apparatus and the liquid processing method of the present invention. This is advantageous in the case where the liquid processing is carried out by consecutively using a plurality of process liquids. Specifically, when it is undesirable for the process liquid used in the preceding stage to be mixed in a certain process liquid, it is possible to clean the chamber before the liquid processing is carried out by changing the process liquid. As a result, it is possible to prevent the process liquid from being contaminated so as to set forth the characteristics of the process liquid, leading to the liquid processing with a high accuracy. It follows that it is possible to maintain a high quality of the cleaned substrate.
Incidentally, in the case of using a chamber of a double wall structure comprising an inside chamber and an outside chamber, it is possible to carry out a liquid processing with a certain process liquid by using one of these chambers, followed by carrying out another liquid processing with another process liquid by using the other chamber. This makes it possible to prevent the different process liquids from being mixed with each other. It is also possible to improve the through-put. In this case, however, a new problem is generated that, in starting a liquid processing applied to substrates of another batch after completion of a series of processing applied to substrates of a certain batch, the chamber used first must be brought back to a clean state. It should be noted in this connection that the liquid processing apparatus of the present invention comprises a cleaning mechanism as pointed out above, making it possible to overcome the above-noted new problem generated by the use of a chamber having a double wall structure. As a result, it is possible to improve the through-put and to lower the processing cost.
According to a third aspect of the present invention, there is provided a liquid processing apparatus for performing a liquid processing by supplying a process liquid to the substrate, comprising a rotor for holding a plurality of substrates a predetermined distance apart from each other and in parallel; a substantially cylindrical outside chamber capable of housing said rotor and fixed to a process position; a substantially cylindrical inside chamber capable of housing said rotor, and capable of being housed in said outside chamber; a cylindrical body capable of being housed inside said inside chamber; a process liquid spurting nozzle for spurting a process liquid onto the substrate held by said rotor; a cleaning liquid spurting nozzle for spurting a cleaning liquid for cleaning said inside chamber; a first sliding mechanism capable of sliding said inside chamber among said process position, said retreat position, and a maintenance position remoter than said retreat position from said process position; a second sliding mechanism capable of sliding said cylindrical body between said retreat position and said maintenance position; a first seal mechanism mounted to one edge surface of said outside chamber in a manner to seal the clearance between said inside chamber and said outside chamber; and a second seal mechanism mounted to an edge surface of said inside chamber in a manner to seal the clearance between said cylindrical body and said inside chamber; wherein said inside chamber is slid between said process position and said maintenance position thereby being held at a predetermined position, and said cylindrical body is slid between said retreat position and said maintenance position thereby being held at a predetermined position, thereby gaining access easily to said first seal mechanism and said second seal mechanism.
In the cleaning processing apparatus of the construction described above, it is possible to gain access easily to the seal mechanism of the chamber. Therefore, it is possible to perform easily the renewing operation of the seal mechanism or the like in the event of, for example, leakage of a chemical liquid through the seal mechanism or in the periodic maintenance operation so as to shorten the working time.
According to a fourth aspect of the present invention, there is provided a liquid processing apparatus for applying a liquid processing by supplying a process liquid to a plurality of substrates, comprising a rotor capable of holding a plurality of substrates a predetermined distance apart from each other; a chamber including a tapered barrel portion, which is tapered such that the outer diameter at one edge surface is larger than that at the other edge surface, and arranged such that the bottom portion of said chamber has a predetermined gradient with said edge surface held substantially vertical; a gas/process liquid spurting nozzle for spurting a gas or a process liquid to the substrates held by said rotor; and an exhaust/drain mechanism mounted to the edge surface of said chamber having a longer outer diameter for exhausting said chamber and for draining the waste liquid from within said chamber; wherein said rotor is capable of being moved into and out of said chamber while holding the substrates substantially vertical such that the main processing surface of the substrate faces the edge surface of said chamber on the side of the longer outer diameter.
According to a fifth aspect of the present invention, there is provided a liquid processing method of a substrate using a liquid processing apparatus including a chamber having a tapered barrel portion, which is tapered such that the outer diameter at one edge surface is larger than that at the other edge surface, and having a predetermined gradient at the bottom portion with said edge surface held substantially vertical, a rotor capable of being moved into and out of said chamber and capable of holding substantially vertical a plurality of substrates a predetermined distance apart from each other in the horizontal direction, a rotating mechanism for rotating said rotor such that the substrates held by said rotor are allowed to rotate within a plane, a gas/process liquid spurting nozzle for spurting a gas or a process liquid onto the substrate held by said rotor, and an exhaust/drain mechanism mounted to the edge surface of said chamber on the side of the longer diameter for exhausting said chamber and for draining the waste liquid from within said chamber, wherein said rotor is arranged within said chamber such that the main processing surfaces of all the substrates held by said rotor are allowed to face the edge surface of said chamber on the side of the longer outer diameter thereby suppressing the stains on the main processing surfaces of said substrates.
According to the liquid processing apparatus and the liquid processing method of the particular construction, the gas and the process liquid spurted into the chamber are allowed to flow from the back surface of the substrate toward the main processing surface. It follows that, even where particles are carried by the gas stream, the particles are unlikely to be attached to the surface of the substrate so as to maintain a high cleanliness on the main processing surface of the substrate, thereby increasing the reliability of the product.